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Development of Rules of Attraction for Intercalated Guest Molecules Inside of a Hydrogen Bonded Framework

机译：氢键构架内插层客体分子吸引规则的发展

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摘要

Supramolecular chemistry has synthesized large and small molecules which host guest molecules for several decades. What started as a way to mimic of enzymes in nature, has exploded into a sea of materials such as porous coordination polymers, low-density metal-organic frameworks, inclusion compounds, and hydrogen bonded frameworks. We previously designed a layered framework consisting of a metal complex with coordinate covalent ligands. These ligands have peripheral carboxylic acid groups which hydrogen bond to organic pillars containing terminal amines. The layered structure is separated by these pillars, which are closed-packed, creating 1-dimensional channels able to co-crystallize molecules. There is interest in selectively binding molecules for separation, catalysis, molecular recognition or transport. How do guests selectively co-crystallize into the framework? Do properties of guest molecules such as size, shape or electronics dictate preference? By establishing a set of selectivity rules, potential applications appear.;In our pursuit, we devised a new way of coupling a thermogravimetric analyzer to a mass spectrometer using solid-phase microextraction fibers. These two instruments can be used together for a fraction existing coupling cost.;By testing guests of different size and shape, we found large guest molecules will co-crystallize over smaller ones. If a guest is too large, the selectivity can become concentration dependent. Maintaining the size difference between two molecules, we changed to geometric isomers. The framework lost selectivity due to poor guest co-crystallization and low guest inclusion rates.;Next, we tested guest molecules whose size and shape was similar but had different electronics. Aromatic guests with electron donating substituents were preferred over those with electron withdrawing groups. The framework could detect subtle changes in the electronic structure, e.g., substituting chloro- for a methyl. Guests containing anchor points, sigma-hole, were showed preference. Selectivity correlated to physical properties such as boiling point and density of the guests containing electron withdrawing substituents.;Finally, we focused on single co-crystallized guests tested by thermogravimetric analysis, gas chromatography, and powder x-ray diffraction. The preferred guests in the previous study contained electron donating groups and high occupancy. Outliers such as iodobenzene were preferred in competition but had low concentrations as a single guest.
机译：超分子化学已经合成了容纳客体分子数十年的大分子和小分子。最初是一种模拟自然界中酶的方法，如今已激增到大量材料中，例如多孔配位聚合物，低密度金属有机骨架，包合物和氢键骨架。我们之前设计了一个分层的框架，该框架由具有配位共价配体的金属配合物组成。这些配体具有外围的羧酸基团，其氢键合到含有末端胺的有机柱上。层状结构由这些柱子隔开，这些柱子是密堆积的，形成了能够使分子共结晶的一维通道。人们对选择性结合分子以进行分离，催化，分子识别或运输感兴趣。访客如何有选择地共沉淀到框架中？客体分子的性质（例如大小，形状或电子学）是否决定了偏好？通过建立一套选择性规则，潜在的应用出现了。在我们的追求中，我们设计了一种使用固相微萃取纤维将热重分析仪与质谱仪耦合的新方法。可以将这两种仪器一起使用，而现有耦合成本却很少。通过测试不同大小和形状的来宾，我们发现大的来宾分子将在较小的分子上共结晶。如果客人太大，则选择性可能取决于浓度。为了保持两个分子之间的大小差异，我们更改为几何异构体。由于差的客体共结晶和低的客体包含率，该框架失去了选择性。具有给电子取代基的芳族客体优于具有吸电子基团的芳族客体。该框架可以检测电子结构中的细微变化，例如用氯取代甲基。包含锚点sigma-hole的来宾显示出偏好。选择性与物理性质（如沸点和含有吸电子取代基的客体的密度）相关。最后，我们将重点放在通过热重分析，气相色谱和粉末X射线衍射测试的单一共结晶客体上。在先前的研究中，首选宾客包含给电子团和高占用率。离群点，例如碘苯，在比赛中被人们偏爱，但它们的单人浓度低。

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  • 作者

    Fischer, Matthew Joseph, Sr.;

  • 作者单位

    University of Missouri - Saint Louis.;

  • 授予单位 University of Missouri - Saint Louis.;
  • 学科 Inorganic chemistry.
  • 学位 Ph.D.
  • 年度 2018
  • 页码 305 p.
  • 总页数 305
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 土壤学;
  • 关键词

  • 入库时间 2022-08-17 11:37:06

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